Phonograph pick-up



May 6, 1930. 7 s. RUBEN PH()IICJCzrIiAPIi PICK-UP Filed June 12, 1929 FIGJ.

FIG2.

Svwemtoz J/IMUEL RUBEN Patented May 6', 1930 SAMUEL RUBEN, NEW YORK, N. Y.

PHONOGBAIPH PICK-UP Application filed June 12,

A This invention relates to an electrical phonograph pick-up device for translating mechanically recorded vibrations into electrical oscillations. An object of the invention is the provision of a device for effecting such translation with distortion and with an efliciency above that of the devices of the prior art.

Broadly, my invention consists of a device for translating mechanically recorded acoustic, vibrations into electrical impulses through changes in the resistance of a euprous oxide electrode in response to pressure changes produced by the movement of a stylus, vibrating through its surface contact with a movin mechanical record. This pickup is nota 1y distinguishable from the carbon type of microphone, known in the prior art, carbon having a low contact and internal resistance; whereas, the device using cuprous oxide has a resistance in the order of many times that of the carbon type, thereby permitting the employment of large voltage charges with minimum current flow.

I have found that to eflect this translation with minimum distortion, it is fundamentally necessary to have an electrode that is controlled by a resilient body as a means of 33 damping its vibrations, in surface contact with a cuprous oxide electrode. The contact between the electrode surfaces must be uninterrupted throughout the various pressure changes produced by the movement of the stylus. This damping effect may be obtained by the use of any suitable resilient material which will insure the continuous surface contact between the electrodes and prevent excessive movement of the stylus. I have found the material best adapted to this use to be rubber, the electrode preferably consisting of a coating upon it of any suitable conductive material at the contacting area, such as a thin layer of deflocculated graphite or of finely ground silver. For maximum efliciency and minimum distortion I have found that a push-pull or two phase electrical arrangement is best adapted to this device.

The invention may be better understood by reference to the following description in con- 1929. Serial 1T0. 870,448.

nection with the acco anying drawings of one embodiment there d fj in which Fig. 1 represents a pick-up connected in an electrical circuit with the push-pull ortwo phase arrangement, Fig. 2 showing the device in a single phase arrangement.

At 1, is a plate or base of insulation material having mounted thereon copper plates 2, with their opposing surfaces coated with enprous oxide layers 3, in surface contact with electrode 4, consisting of a coating of deflocculated graphite upon a rubber block, attached to stylus 6, by band 5. Stylus 6, is rotatably mounted on plate 7, which is mounted on plate 1, rubber sheets 8, being placed between the plate and the stylus to frictionally hold the stylus. Element 9 is a ferrule for mounting the device on a supporting arm of a phonograph or other reproducing apparatus. In the push-pull circuit is battery 10 for furnishing a potential to the electrodes 3 and 4, 11 being a conventional two phase type of transformer in the output circuit; that shown in Fig. 2 being a single phase type of transformer.

In the operation of the device in both systerns the total resistance of the device is initially the combined contact and crystal internal resistance of the copper oxide electrode. \Vith increased pressure upon the cuprous oxide electrode, due to the negative contact resistance coefficient of, this material with pressure, there is an increase of current flow through the oxide.

What I claim is: g

1. A device for translating mechanically recorded vibrations into electrical oscillations comprising a base supporting a rotatably mounted stylus, constituting a vibrationresponsive electrode and a cooperating cuprous oxide electrode in surface contact with the other electrode.

2. A device for translating mechanically recorded vibrations into electrical oscillations, comprising a base supporting a rotatably mounted stylus, constituting a vibration-responsive electrode and a cooperating electrode in surface contact with the other electrode one of said electrodes being composed of cuprous oxide and means for damping the movement of the stylus.

3. A device for translating mechanically recorded vibrations into electrical oscillations, comprising a base supporting a stylus, constituting an electrode, and a cuprous oxide electrode, held in surface contact with the other electrode by a resilient body.

4. A device for translating mechanically recorded; vibrations into electrical oscillations comprising a base support, a stylus constituting a vibratory electrode, two cooperating electrodes each in surface contact with said stylus, the two cooperating electrodes being composed at the surface contact areas of cuprous oxide.

5. A device for translating mechanically recorded vibrations into electrical oscillations comprising a base support, a stylus constituting a vibratory electrode, controlled by a resilient body, two cooperating electrodes each in surface contact with said stylus, the two cooperating electrodes being composed at the said contact areas of cuprous oxide.

6. In a phonograph pick-up, a stylus constituting a vibratory electrode and two cooperating electrodes mounted in surface contact with two sides of the vibratory electrode, two of said electrode contact areas being composed of cuprous oxide.

7. In a phonograph pick-up, a stylus constituting a vibratory electrode, controlled by a resilient body and two cooperating electrodes in surface contact with two sides of the vibratory electrode, two of the electrode contact areas being composed of cuprous oxide.

8. In a phonograph pick-up, a stylus constituting a vibratory electrode and two cooperating electrodes mounted in surface contact with two sides of the vibratory electrode, two of said electrode contact areas being composed of a material, the contact resistance of which varies with the pressure applied, the vibratory electrode being so mounted that the movement of the said electrode contact area of the vibratory electrode in one direction causes an increased contact resistance of the material at one of said electrode contact areas and a decreased contact resistance at the other electrode contact area.

9. In a phonograph pick-up, a stylus constituting a vibratory electrode, controlled by a resilient body and two cooperating electrodes in surface contact with two sides of the vibratory electrode, two of the electrode contact areas being com osed of a material, the contact resistance 0 which varies with the pressure applied, the vibratory electrode being so mounted that the movement of the said electrode contact area of the vibratory electrode in one direction causes an increased contact resistance of the material at one of said electrode contact areas and a decreased contact resistance at the other electrode contact area.

and a decreased contact resistance at the other electrode contact area.

11. Ina phonograph pick-up, a stylus constituting a vibratory electrode, controlled by a resilient body and two cooperating electrodes in surface contact with two sides of the vibratory electrode, two of the electrode contact areas being composed of cuprous oxide, the vibratory electrode being so mounted that the movement of the said electrode contact area of the vibratory electrode in one direction' causes an increased contact resistance of the cuprous oxide at one of said electrode contact areas and a decreased contact resistance at the other electrode contact area.

12. A phonograph pick-up havin sure sensitive electrode composed o oxide. 7 V

In testimony whereof, I, SAMUEL RUBEN, have signed my name to this specification this 10th day of June, 1929.

SAMUEL RUBEN.

a prescuprous 

